Front
NOTE: Pad wear warning indicators are incorporated into the front and rear right hand inboard pads.REMOVE CALIPER
1. Loosen the front wheel retaining nuts, using a suitable hydraulic floor jack raise the front of the vehicle and lower onto axle stands and remove the wheels.
2. Expose the two flexible brake hoses by moving the coiled protective covering.
3. Using a recognized hose clamp, clamp both hoses to prevent loss of brake fluid, disconnect the rigid brake pipes from the flexible hoses, seal the ends of the hoses and pipe openings to prevent ingress of dirt. (If necessary the two rigid brake pipes to the caliper can be disconnected when the caliper is removed from the swivel pin housing).
4. Disconnect the pad wear warning indicator (front right hand side only).
5. Remove the retaining pins and springs, withdraw the pads. If the same pads are to be refitted, identify them for assembly to their original locations.
6. Remove the two bolts and withdraw the caliper from the disc.
NOTE: Do not separate the caliper halves
7. Clean the outer surfaces of the caliper with aerosol brake cleaner.
8. Using special tool 18G672, clamp the pistons in the inboard half of the caliper and gently, keeping fingers clear, and with CAUTION, apply air pressure to the fluid inlet port to expel the rim half pistons. Since it is unlikely that all pistons will expel at the same time, regulate the rate with a suitable piece of wood between the appropriate piston and caliper.
9. Finally, remove the pistons keeping them identified with their respective bores.
10. Remove the wiper seal retainer by inserting a blunt screwdriver between the retainer and the seal and pry the retainer carefully from the mouth of the bore.
11. Taking care not to damage the seal grooves, extract the wiper seal and fluid seal.
12. Clean the bores, pistons and particularly the seal grooves with clean brake fluid or aerosol brake cleaner only. If the caliper or pistons are corroded or if their condition is not perfect new parts must be fitted.
Assemble Outboard Pistons
13. Coat a new fluid seal with a suitable disc brake lubricant. Ease the seal into the groove in the bore using only the fingers and ensure that it is properly seated. The fluid seal and the groove are not the same that when the seal is seated it feels raised to the touch at the edge furthest away from the mouth of the bore.
14. Coat the appropriate piston with disc brake lubricant and insert it squarely into the bore by hand only. Do not tilt - the piston during insertion and leave approximately 8mm (0.312 inch) projecting from the bore.
15. Coat a new wiper seal with disc brake lubricant and fit it to a new seal retainer. Slide the assembly, seal first, over the protruding piston and into the bore recess. Remove the piston clamp from the mounting half and use the clamp to press home the seal retainer and piston.
Mounting Inboard Pistons
16. Clamp the outboard pistons and carry out the same procedure as for removing and fitting the outboard pistons and seals, instructions B to 15.
FIT CALIPERS AND PADS TO VEHICLE
17. Fit the caliper to the axle and secure with the two bolts tightening evenly to 65-80 Nm (48-59 ft lb).
18. Connect the brake flexible hoses to the caliper and tighten to 12 Nm (9 ft lb).
19. Remove the clamps from the hoses.
20. Lightly coat the back and edges of the pads with a suitable disc brake lubricant carefully avoiding the friction material.
21. Insert the pads and retaining springs, secure in position using new retaining pins and open out the ends. Note the correct position of the retaining springs.
NOTE: Ensure that the friction pad with the wear indicator is fitted to the inboard side of the front right hand caliper
22. Reconnect the pad wear indicator electrical plug.
23. Bleed both the primary and secondary brake systems.
24. When the foregoing instructions have been completed on all calipers, press the brake pedal firmly several times to locate the friction pads.
25. Fit the road wheels, remove the axle stands and finally tighten the road wheel nuts.
26. Road test the vehicle, remembering that if new friction pads have been fitted they are not bedded-in and may take several hundred miles before the brakes are at maximum efficiency.